View source for 3fk7


==Crystal structure of TetR triple mutant (H64K, S135L, S138I) in complex with 4-ddma-atc==
<StructureSection load='3fk7' size='340' side='right'caption='[[3fk7]], [[Resolution|resolution]] 2.06&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3fk7]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3FK7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3FK7 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.06&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=4DM:(4AS,12AS)-3,10,11,12A-TETRAHYDROXY-6-METHYL-1,12-DIOXO-1,4,4A,5,12,12A-HEXAHYDROTETRACENE-2-CARBOXAMIDE'>4DM</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3fk7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3fk7 OCA], [https://pdbe.org/3fk7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3fk7 RCSB], [https://www.ebi.ac.uk/pdbsum/3fk7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3fk7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TETR2_ECOLX TETR2_ECOLX] TetR is the repressor of the tetracycline resistance element; its N-terminal region forms a helix-turn-helix structure and binds DNA. Binding of tetracycline to TetR reduces the repressor affinity for the tetracycline resistance gene (tetA) promoter operator sites.[https://www.uniprot.org/uniprot/TETR4_ECOLX TETR4_ECOLX] TetR is the repressor of the tetracycline resistance element; its N-terminal region forms a helix-turn-helix structure and binds DNA. Binding of tetracycline to TetR reduces the repressor affinity for the tetracycline resistance gene (tetA) promoter operator sites.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/fk/3fk7_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3fk7 ConSurf].
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== Publication Abstract from PubMed ==
The bacterial tetracycline transcription regulation system mediated by the tetracycline repressor (TetR) is widely used to study gene expression in prokaryotes and eukaryotes. To study multiple genes in parallel, a triple mutant TetR(K(64)L(135)I(138)) has been engineered that is selectively induced by the synthetic tetracycline derivative 4-de-dimethylamino-anhydrotetracycline (4-ddma-atc) and no longer by tetracycline, the inducer of wild-type TetR. In the present study, we report the crystal structure of TetR(K(64)L(135)I(138)) in the absence and in complex with 4-ddma-atc at resolutions of 2.1 A. Analysis of the structures in light of the available binding data and previously reported TetR complexes allows for a dissection of the origins of selectivity and specificity. In all crystal structures solved to date, the ligand-binding position, as well as the positioning of the residues lining the binding site, is extremely well conserved, irrespective of the chemical nature of the ligand. Selective recognition of 4-ddma-atc is achieved through fine-tuned hydrogen-bonding constraints introduced by the His64--&gt;Lys substitution, as well as a combination of hydrophobic effect and the removal of unfavorable electrostatic interactions through the introduction of Leu135 and Ile138.

Structural origins for selectivity and specificity in an engineered bacterial repressor-inducer pair.,Klieber MA, Scholz O, Lochner S, Gmeiner P, Hillen W, Muller YA FEBS J. 2009 Oct;276(19):5610-21. Epub 2009 Aug 27. PMID:19712110<ref>PMID:19712110</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3fk7" style="background-color:#fffaf0;"></div>

==See Also==
*[[Tetracycline repressor protein 3D structures|Tetracycline repressor protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Gmeiner P]]
[[Category: Hillen W]]
[[Category: Klieber MA]]
[[Category: Lochner S]]
[[Category: Muller YA]]
[[Category: Scholz O]]